I played the first one on 3DS and couldn't really get into it, which is why I skipped the sequel. It's really hard to describe what I didn't like about the game though. It wasn't too hard (I enjoyed its difficulty), the graphics were fine, the music was good (not as amazing as I hear some people saying, but there were definitely a few great ones), and the levels were varied enough to keep things interesting so it managed to avoid my complaints with the New Super Mario series. But after a few hours of playing it I just wasn't really enjoying playing it.
For me it legitimately might have been a case of being too hyped for me before I played the first one. I had a similar reaction when I finally played Spelunky after hearing about it for a year or so about how amazing it was, which made me pick it up only to find out that it wasn't really my cup of tea. I can appreciate the strengths of the game, but my personally experience just wasn't as enjoyable as I had expected.